Catalyst system for producing aromatic carbonates

ABSTRACT

A catalyst system for economically producing aromatic carbonates from aromatic hydroxy compounds. In one embodiment, the present invention provides a carbonylation catalyst system that includes a catalytic amount of an inorganic co-catalyst containing bismuth. In various alternative embodiments, the carbonylation catalyst system can include an effective amount of a palladium source and an effective amount of a halide composition. Further alternative embodiments can include catalytic amounts of various inorganic co-catalyst combinations.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of application Ser. No. 09/301,702, filedApr. 29, 1999, now U.S. Pat. No. 6,114,563, entitled “METHOD ANDCATALYST SYSTEM FOR PRODUCING AROMATIC CARBONATES” and, accordingly,claims priority to and the benefit of the filing date of saidapplication under 35 U.S.C. §120. The parent application is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to a catalyst system for producingaromatic carbonates and, more specifically, to a catalyst system forproducing diaryl carbonates through the carbonylation of aromatichydroxy compounds.

2. Discussion of Related Art

Aromatic carbonates find utility, inter alia, as intermediates in thepreparation of polycarbonates. For example, a popular method ofpolycarbonate preparation is the melt transesterification of aromaticcarbonates with bisphenols. This method has been shown to beenvironmentally superior to previously used methods which employedphosgene, a toxic gas, as a reagent and chlorinated aliphatichydrocarbons, such as methylene chloride, as solvents.

Various methods for preparing aromatic carbonates have been previouslydescribed in the literature and/or utilized by industry. A method thathas enjoyed substantial popularity in the literature involves the directcarbonylation of aromatic hydroxy compounds with carbon monoxide andoxygen. In general, practitioners have found that the carbonylationreaction requires a rather complex catalyst system. For example, in U.S.Pat. No. 4,187,242, which is assigned to the assignee of the presentinvention, Chalk reports that a carbonylation catalyst system shouldcontain a Group VIII B metal, such as ruthenium, rhodium, palladium,osmium, iridium, platinum, or a complex thereof. Further refinements tothe carbonylation reaction include the identification of organicco-catalysts, such as terpyridines, phenanthrolines, quinolines andisoquinolines in U.S. Pat. No. 5,284,964 and the use of certain halidecompounds, such as quaternary ammonium or phosphonium halides in U.S.Pat. No. 5,399,734, both patents also being assigned to the assignee ofthe present invention.

The economics of the carbonylation process is strongly dependent on thenumber of moles of aromatic carbonate produced per mole of Group VIII Bmetal utilized (i.e. “catalyst turnover”). Consequently, much work hasbeen directed to the identification of efficacious inorganicco-catalysts that increase catalyst turnover. In U.S. Pat. No.5,231,210, which is also assigned to General Electric Company, Joyce etal. report the use of a cobalt pentadentate complex as an inorganicco-catalyst (“IOCC”). In U.S. Pat. No. 5,498,789, Takagi et al. reportthe use of lead as an IOCC. In U.S. Pat. No. 5,543,547, Iwane et al.report the use of trivalent cerium as an IOCC. In U.S. Pat. No.5,726,340, Takagi et al. report the use of lead and cobalt as a binaryIOCC system. In Japanese Unexamined Patent Application No. 10-316627,Yoneyama et al. report the use of manganese and the combination ofmanganese and lead as IOCC's.

The literature is silent, however, as to the role of the IOCC in thecarbonylation reaction (i.e. the reaction mechanism). Accordingly,meaningful guidance regarding the identification of additional IOCCsystems is cursory at best. Periodic table groupings have failed toprovide guidance in identifying additional IOCC's. For example, U.S.Pat. No. 5,856,554 provides a general listing of possible IOCCcandidates, yet further analysis has revealed that many of the members(and combinations of members) of the recited groups (i.e., Groups IV Band V B) do not catalyze the carbonylation reaction. Therefore, due tothe lack of guidance in the literature, the identification of effectivecarbonylation catalyst systems has become a serendipitous exercise.

As the demand for high performance plastics has continued to grow, newand improved methods of providing product more economically are neededto supply the market. In this context, various processes and catalystsystems are constantly being evaluated; however, the identities ofimproved and/or additional effective catalyst systems for theseprocesses continue to elude the industry. Consequently, a long felt, yetunsatisfied need exists for new and improved methods and catalystsystems for producing aromatic carbonates and the like.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a catalyst system forproducing aromatic carbonates. In one embodiment, the present inventionprovides a carbonylation catalyst system that includes a catalyticamount of an inorganic co-catalyst containing bismuth.

In various alternative embodiments, the carbonylation catalyst systemcan include an effective amount of a palladium source and an effectiveamount of a halide composition. Further alternative embodiments caninclude catalytic amounts of various co-catalyst combinations, such asbismuth and copper; bismuth, copper, and titanium; bismuth, copper andiron; bismuth and cerium; bismuth and manganese; bismuth, manganese, andeuropium; bismuth, manganese, and iron; bismuth, manganese and cerium;bismuth and europium; bismuth and nickel; bismuth and zinc; bismuth andiron; bismuth and cobalt; bismuth and iridium; bismuth and ruthenium;bismuth and rhodium; and bismuth and zirconium.

BRIEF DESCRIPTION OF THE DRAWING

Various features, aspects, and advantages of the present invention willbecome more apparent with reference to the following description,appended claims, and accompanying drawing, wherein the FIGURE is aschematic view of a device capable of performing an aspect of anembodiment of the present invention.

DETAILED DESCRIPTION

The present invention is directed to a catalyst system for producingaromatic carbonates. In one embodiment, the carbonylation catalystsystem includes a catalytic amount of an inorganic co-catalystcontaining bismuth. In alternative embodiments, the catalyst system caninclude an effective amount of a Group VIII B metal and an effectiveamount of a halide composition.

Unless otherwise noted, the term “effective amount,” as used herein,includes that amount of a substance capable of either increasing(directly or indirectly) the yield of the carbonylation product orincreasing selectivity toward an aromatic carbonate. Optimum amounts ofa given reactant can vary based on reaction conditions and the identityof other constituents yet can be readily determined in light of thediscrete circumstances of a given application.

Aromatic hydroxy compounds which may be used in the practice of thepresent invention include aromatic mono or polyhydroxy compounds, suchas phenol, cresol, xylenol, resorcinol, hydroquinone, and bisphenol A.Aromatic organic mono hydroxy compounds are preferred, with phenol beingmore preferred.

In various preferred embodiments, the carbonylation catalyst system cancontain at least one constituent from the Group VIII B metals or acompound thereof. A preferred Group VIII B constituent is an effectiveamount of a palladium source. In various embodiments, the palladiumsource may be in elemental form, or it may be employed as a palladiumcompound. Accordingly, palladium black or elemental palladium depositedon carbon may be used as well as palladium halides, nitrates,carboxylates, oxides and palladium complexes containing carbon monoxide,amines, phosphines or olefins. As used herein, the term “complexes”includes coordination or complex compounds containing a central ion oratom. The complexes may be nonionic, cationic, or anionic, depending onthe charges carried by the central atom and the coordinated groups.Other common names for these complexes include complex ions (ifelectrically charged), Werner complexes, and coordination complexes.

In various applications, it may be preferable to utilize palladium (II)salts of organic acids, including carboxylates with C₂₋₆ aliphaticacids. Palladium(II) acetylacetonate is also a suitable palladiumsource. Preferably, the amount of Group VIII B metal source employedshould be sufficient to provide about 1 mole of metal per 800-10,000moles of aromatic hydroxy compound. More preferably, the proportion ofGroup VIII B metal source employed should be sufficient to provide about1 mole of metal per 2,000-5,000 moles of aromatic hydroxy compound.

The carbonylation catalyst system may further contain an effectiveamount of a halide composition, such as an organic halide salt. Invarious preferred embodiments, the halide composition can be an organicbromide salt. The salt may be a quaternary ammonium or phosphonium salt,or a hexaalkylguanidinium bromide. In various embodiments, α,ω-bis(pentaalkylguanidinium)alkane salts may be preferred. Suitableorganic halide compositions include tetrabutylammonium bromide,tetraethylammonium bromide, and hexaethylguanidinium bromide. Inpreferred embodiments, the carbonylation catalyst system can containbetween about 5 and about 1000 moles of bromide per mole of palladiumemployed, and, more preferably, between about 50 and about 150 molarequivalents of bromide are used.

The formation of diaryl carbonates in a carbonylation reaction can beaccompanied by the formation of by-products, such as bisphenols, invarying proportions. In order to increase selectivity to diarylcarbonate, various organic co-catalysts may be incorporated in thecarbonylation catalyst system. Depending on the application, suitableorganic co-catalyst may include various phosphine, quinone, terpyridine,phenanthroline, quinoline and isoquinoline compounds and theirderivatives, such as 2,2′:6′,2-terpyridine,4′-methylthio-9,2′:6′,2-terpyridine, 2,2′:6′,2-terpyridine N-oxide,1,10-phenanthroline, 9,4,7,8-tetramethyl-1,10-phenanthroline,4,7-diphenyl-1,10-phenanthroline and3,4,7,8-tetramethyl-1,10-phenanthroline.

The carbonylation catalyst system includes a catalytic amount of aninorganic co-catalyst (IOCC) containing bismuth. In addition to bismuthper se, it has been discovered that certain IOCC combinations caneffectively catalyze the carbonylation reaction. Such IOCC combinationsinclude bismuth and copper; bismuth, copper, and titanium; bismuth,copper and iron; bismuth and cerium; bismuth and manganese; bismuth,manganese, and europium; bismuth, manganese, and iron; bismuth,manganese and cerium; bismuth and europium; bismuth and nickel; bismuthand zinc; bismuth and iron; bismuth and cobalt; bismuth and iridium;bismuth and ruthenium; bismuth and rhodium; and bismuth and zirconium.

An IOCC can be introduced to the carbonylation reaction in variousforms, including salts and complexes, such as tetradentate,pentadentate, hexadentate, or octadentate complexes. Illustrative formsmay include oxides, halides, carboxylates, diketones (includingbeta-diketones), nitrates, complexes containing carbon monoxide orolefins, and the like. Suitable beta-diketones include those known inthe art as ligands for the IOCC metals of the present invention.Examples include, but are not limited to, acetylacetone, benzoylacetone,dibenzoylmethane, diisobutyrylmethane, 2,2-dimethylheptane-3,5-dione,2,2,6-trimethylheptane-3,5-dione, dipivaloylmethane, andtetramethylheptanedione. The quantity of ligand is preferably not suchthat it interferes with the carbonylation reaction itself, with theisolation or purification of the product mixture, or with the recoveryand reuse of catalyst components (such as palladium). An IOCC may beused in its elemental form if sufficient reactive surface area can beprovided. In embodiments employing supported palladium, it is noted thatthe bismuth-based IOCC provides a discrete, catalytic source of bismuthin a form favorable for such catalysis.

IOCC's are included in the carbonylation catalyst system in catalyticamounts. In this context a “catalytic amount” is an amount of IOCC (orcombination of IOCC's) that increases the number of moles of aromaticcarbonate produced per mole of Group VIII B metal utilized; increasesthe number of moles of aromatic carbonate produced per mole of halideutilized; or increases selectivity toward aromatic carbonate productionbeyond that obtained in the absence of the IOCC (or combination ofIOCC's). Optimum amounts of an IOCC in a given application will dependon various factors, such as the identity of reactants and reactionconditions. For example, when palladium is included in the reaction, themolar ratio of bismuth relative to palladium at the initiation of thereaction is preferably between about 0.1 and about 100. AdditionalIOCC's may be used in the carbonylation catalyst system, provided theadditional IOCC does not deactivate (i.e. “poison”) the original IOCC.

The carbonylation reaction can be carried out in a batch reactor or acontinuous reactor system. Due in part to the low solubility of carbonmonoxide in organic hydroxy compounds, such as phenol, it is preferablethat the reactor vessel be pressurized. In preferred embodiments, gascan be supplied to the reactor vessel in proportions of between about 2and about 50 mole percent oxygen, with the balance being carbonmonoxide. Additional gases may be present in amounts that do notdeleteriously affect the carbonylation reaction. The gases may beintroduced separately or as a mixture. A total pressure in the range ofbetween about 10 and about 250 atmospheres is preferred. Drying agents,typically molecular sieves, may be present in the reaction vessel.Reaction temperatures in the range of between about 60° C. and about150° C. are preferred. Gas sparging or mixing can be used to aid thereaction.

In order that those skilled in the art will be better able to practicethe present invention reference is made to the FIGURE, which shows anexample of a continuous reactor system for producing aromaticcarbonates. The symbol “V” indicates a valve and the symbol “P”indicates a pressure gauge.

The system includes a carbon monoxide gas inlet 10, an oxygen inlet 11,a manifold vent 12, and an inlet 13 for a gas, such as carbon dioxide. Areaction mixture can be fed into a low pressure reservoir 20, or a highpressure reservoir 21, which can be operated at a higher pressure thanthe reactor for the duration of the reaction. The system furtherincludes a reservoir outlet 22 and a reservoir inlet 23. The gas feedpressure can be adjusted to a value greater than the desired reactorpressure with a pressure regulator 30. The gas can be purified in ascrubber 31 and then fed into a mass flow controller 32 to regulate flowrates. The reactor feed gas can be heated in a heat exchanger 33 havingappropriate conduit prior to being introduced to a reaction vessel 40.The reaction vessel pressure can be controlled by a back pressureregulator 41. After passing through a condenser 25, the reactor gaseffluent may be either sampled for further analysis at valve 42 orvented to the atmosphere at valve 50. The reactor liquid can be sampledat valve 43. An additional valve 44 can provide further system control,but is typically closed during the gas flow reaction.

In the practice of one embodiment of the invention, the carbonylationcatalyst system and aromatic hydroxy compound are charged to the reactorsystem. The system is sealed. Carbon monoxide and oxygen are introducedinto an appropriate reservoir until a preferred pressure (as previouslydefined) is achieved. Circulation of condenser water is initiated, andthe temperature of the heat exchanger 33 (e.g., oil bath) can be raisedto a desired operating temperature. A conduit 46 between heat exchanger33 and reaction vessel 40 can be heated to maintain the desiredoperating temperature. The pressure in reaction vessel 40 can becontrolled by the combination of reducing pressure regulator 30 and backpressure regulator 41. Upon reaching the desired reactor temperature,aliquots can be taken to monitor the reaction.

EXAMPLES

The following examples are included to provide additional guidance tothose skilled in the art in practicing the claimed invention. While someof the examples are illustrative of various embodiments of the claimedinvention, others are comparative and are identified as such. Theexamples provided are merely representative of the work that contributesto the teaching of the present application. Accordingly, these examplesare not intended to limit the invention as defined in the appendedclaims, in any manner. Unless otherwise specified, all parts are byweight, and all equivalents are relative to palladium. Reaction productswere verified by gas chromatography. All reactions were carried out in aglass batch reactor at 90-100° C. in a 10% O₂ in CO atmosphere at anoperating pressure of 95-102 atm. Reaction time was generally 2-3 hours.

As discussed supra, the economics of aromatic carbonate production isdependent on the number of moles of aromatic carbonate produced per moleof Group VIII B metal utilized. In the following examples, the aromaticcarbonate produced is diphenylcarbonate (DPC) and the Group VIII B metalutilized is palladium. For convenience, the number of moles of DPCproduced utilized is palladium utilized is referred to as the palladiumturnover number (Pd TON).

Baseline Example

In order to determine the comparative efficacy of various embodiments ofthe present invention, baseline data were produced by adding, at ambientconditions, 0.25 mM palladium(II) acetylacetonate and various amounts ofhalide compositions to a glass reaction vessel containing phenol. Thereactants were heated to 100° C. for 3 hours in a 10% oxygen in carbonmonoxide atmosphere. After the reaction, samples were analyzed for DPCby gas chromatography producing the following results:

HegBr Experiment No. Pd ppm Equivalents Pd TON 1 25  0 82.3 2 25  3075.5 3 25  60 50.3 4 25 120 46.3 5 25 240 44.2 6 25 600 38.7

Example 1

Diphenyl carbonate was produced by adding, at ambient conditions,palladium(II) acetylacetonate, hexaethylguanidinium bromide (“HegBr”),and bismuth(II) tetramethylheptanedionate as an inorganic co-catalyst toa glass reaction vessel containing phenol. The reactants were heated to100° C. for 3 hours in a 10% oxygen in carbon monoxide atmosphere. Afterthe reaction, samples were analyzed for DPC by gas chromatography. Thefollowing results were observed:

Pd Experiment No. Ppm Bi Equivalents Br Equivalents Pd TON 1 25 14 30230 2 25 14 60 266 3 25 14 120  285 4 25 28 30 243 5 25 28 120  368

The various reaction condition show that a Pd TON at least as high as368 can be obtained utilizing bismuth as an IOCC. Based on the resultsof these experiments, it is evident that an IOCC containing bismuth caneffectively catalyze the carbonylation reaction.

Example 2

The general procedure of Example 1 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate and 14 equivalents of copper in theform of copper(II) acetylacetonate. The Pd TON was found to be 381, thusshowing that the IOCC combination of bismuth and copper can effectivelycatalyze the carbonylation reaction.

Example 3

The general procedure of Examples 1 and 2 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate, 14 equivalents of copper in theform of copper(II) acetylacetonate, and 14 equivalents of titanium inthe form of titanium(IV) oxide acetylacetonate. The Pd TON was found tobe 426, thus showing that the IOCC combination of bismuth, copper, andtitanium can effectively catalyze the carbonylation reaction.

Example 4

The general procedure of Examples 1-3 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate, 14 equivalents of copper in theform of copper(II) acetylacetonate, and 14 equivalents of iron in theform of iron(III) acetylacetonate. The Pd TON was found to be 929, thusshowing that the IOCC combination of bismuth, copper, and iron caneffectively catalyze the carbonylation reaction.

Example 5

The general procedure of Examples 1-4 was repeated with 25 ppmpalladium(I) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate and 14 equivalents of cerium in theform of cenium(III) acetylacetonate. The Pd TON was found to be 734,thus showing that the IOCC combination of bismuth and cerium caneffectively catalyze the carbonylation reaction.

Example 6

The general procedure of Examples 1-5 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate and 14 equivalents of manganese inthe form of manganese(III) acetylacetonate. The Pd TON was found to be709, thus showing that the IOCC combination of bismuth and manganese caneffectively catalyze the carbonylation reaction.

The reaction was repeated with 25 ppm palladium(II) acetylacetonate andvarious amounts of bromide and IOCC to provide the following results:

Experiment Mn(acac)₃ Bi(TMHD)₂ HegBr No. Equivalents EquivalentsEquivalents Pd TON 1 14 2.8 120 645 2 14 2.8  30 583 3 28 5.6 120 728 428 5.6  30 564 5 2.8 14 120 818 6 2.8 14  30 477 7 5.6 28 120 1075  85.6 28  30 556

Based on the results of these experiments, it is evident that thecombination of higher bismuth content, lower manganese content, andhigher bromide content may provide superior performance under certainreaction conditions.

Example 7

The general procedure of Examples 1-6 was repeated with 25 ppmpalladium(II) acetylacetonate and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate, 14 equivalents of manganese in theform of manganese(III) acetylacetonate, and 14 equivalents of europiumin the form of europium(III) acetylacetonate. No bromide was added. ThePd TON was found to be 198, thus showing that the IOCC combination ofbismuth, manganese, and europium can effectively catalyze thecarbonylation reaction even in the absence of bromide.

The reaction was repeated with 25 ppm palladium(II) acetylacetonate andvarious amounts of bromide and IOCC to provide the following results:

Exp. Mn(acac)₃ Bi(TMHD)₂ Eu(acac)₃ HegBr No. Equivalents EquivalentsEquivalents Equivalents Pd TON  1 14  4  4 120 806  2 14  4  4 240 600 3 14  4 14 120 1066   4 14  4 14 240 954  5 14  4 56 120 757  6 14  456 240 603  7 14 14  4 120 920  8 14 14  4 240 833  9 14 14 14 120 1126 10 14 14 14 240 1098  11 14 14 56 120 1339  12 14 14 56 240 1289  13 1456  4 120 864 14 14 56  4 240 1150  15 14 56 14 120 1275  16 14 56 14240 1408  17 14 56 56 120 1681  18 14 56 56 240 2071  19 28  4  4 120769 20 28  4  4 240 626 21 28  4 14 120 569 22 28  4 14 240 424 23 28  456 120 333 24 28  4 56 240 244 25 28 14  4 120 905 26 28 14  4 240 77227 28 14 14 120 890 28 28 14 14 240 975 29 28 14 56 120 711 30 28 14 56240 545 31 28 56  4 120 720 32 28 56  4 240 967 33 28 56 14 120 952 3428 56 14 240 1359  35 28 56 56 120 1356  36 28 56 56 240 1524 

The various reaction conditions show that a Pd TON at least as high as2071 can be obtained utilizing the IOCC combination of bismuth,manganese, and europium.

Example 8

The general procedure of Examples 1-7 was repeated with 25 ppmpalladium(II)acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate, 14 equivalents of manganese in theform of manganese(III) acetylacetonate, and 14 equivalents of iron inthe form of iron(III) acetylacetonate. The Pd TON was found to be 1003,thus showing that the IOCC combination of bismuth, manganese, and ironcan effectively catalyze the carbonylation reaction.

Example 9

The general procedure of Examples 1-8 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate and 14 equivalents of europium inthe form of europium(III) acetylacetonate. The Pd TON was found to be376, thus showing that the IOCC combination of bismuth and europium caneffectively catalyze the carbonylation reaction.

Example 10

The general procedure of Examples 1-9 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate and 14 equivalents of nickel in theform of nickel(II) acetylacetonate. The Pd TON was found to be 265, thusshowing that the IOCC combination of bismuth and nickel can effectivelycatalyze the carbonylation reaction.

Example 11

The general procedure of Examples 1-10 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate, 14 equivalents of manganese in theform of manganese(III) acetylacetonate, and 14 equivalents of cerium inthe form of cerium(III) acetylacetonate. The Pd TON was found to be 817,thus showing that the IOCC combination of bismuth, manganese, and ceriumcan effectively catalyze the carbonylation reaction.

Example 12

The general procedure of Examples 1-11 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate and 14 equivalents of zinc in theform of zinc((II) acetylacetonate. The Pd TON was found to be 357, thusshowing that the IOCC combination of bismuth and zinc can effectivelycatalyze the carbonylation reaction.

Example 13

The general procedure of Examples 1-12 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate and 14 equivalents of iron in theform of iron(III) acetylacetonate. The Pd TON was found to be 578, thusshowing that the IOCC combination of bismuth and iron can effectivelycatalyze the carbonylation reaction. The reaction was repeated with 25ppm palladium(II) acetylacetonate and various amounts of bromide andIOCC to provide the following results:

Experiment Fe(acac)₃ Bi(TMHD)₂ HegBr No. Equivalents EquivalentsEquivalents Pd TON 1 2.8 14 120 372 2 2.8 14  30 216 3 5.6 28 120 368 45.6 28  30 231 5 14 2.8 120 208 6 14 2.8  30 474 7 28 5.6 120 377 8 285.6  30 732

Based on the results of these experiments, it is evident that thecombination of lower bismuth content, higher iron content, and lowerbromide content may provide superior performance under certain reactionconditions.

Example 14

The general procedure of Examples 1-13 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate and 14 equivalents of cobalt in theform of cobalt(IT) acetylacetonate. The Pd TON was found to be 122, thusshowing that the IOCC combination of bismuth and cobalt can effectivelycatalyze the carbonylation reaction.

Example 15

The general procedure of Examples 1-14 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate and 14 equivalents of iridium inthe form of iridium(III) acetylacetonate. The Pd TON was found to be267, thus showing that the IOCC combination of bismuth and iridium caneffectively catalyze the carbonylation reaction.

Example 16

The general procedure of Examples 1-15 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate and 14 equivalents of ruthenium inthe form of ruthenium(III) acetylacetonate. The Pd TON was found to be200, thus showing that the IOCC combination of bismuth and ruthenium caneffectively catalyze the carbonylation reaction.

Example 17

The general procedure of Examples 1-16 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate and 14 equivalents of rhodium inthe form of rhodium(III) acetylacetonate. The Pd TON was found to be212, thus showing that the IOCC combination of bismuth and rhodium caneffectively catalyze the carbonylation reaction.

Example 18

The general procedure of Examples 1-17 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate and 14 equivalents of zirconium inthe form of zirconium(IV) acetylacetonate. The Pd TON was found to be404, thus showing that the IOCC combination of bismuth and zirconium caneffectively catalyze the carbonylation reaction.

Comparative Example A

It has been determined that several potential IOCC candidates do notcatalyze the carbonylation reaction and in fact may poison an otherwiseeffective IOCC combination. For example, the general procedure ofExamples 1-18 was repeated with 25 ppm palladium(II) acetylacetonate, 60equivalents of bromide in the form of hexaethylguanidinium bromide, and14 equivalents of antimony in the form of antimony(III)bromide as apotential IOCC candidate. The Pd TON was found to be zero, therebyshowing that Sb(III) does not effectively catalyze the carbonylationreaction at the conditions used.

Comparative Example B

The general procedure of Examples 1-18 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and the following IOCC combination: 14equivalents of bismuth in the form ofbismuth(II)tetramethylheptanedionate and 14 equivalents of antimony inthe form of SbBr₃. The Pd TON was found to be zero, thereby showingthat, in addition to failing to effectively catalyze the carbonylationreaction as a sole IOCC, Sb(III) can poison an otherwise effective IOCC(i.e. bismuth) at the conditions used.

Comparative Example C

The general procedure of Examples 1-18 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and 14 equivalents of vanadium in the formof vanadium(III) acetylacetonate as a potential IOCC candidate. The PdTON was found to be zero, thereby showing that V(III) does noteffectively catalyze the carbonylation reaction at the conditions used.

Comparative Example D

The general procedure of Examples 1-18 was repeated with 25 ppmpalladium(II) acetylacetonate, 60 equivalents of bromide in the form ofhexaethylguanidinium bromide, and 14 equivalents of vanadium in the formof vanadium(IV) oxide acetylacetonate as a potential IOCC candidate. ThePd TON was found to be zero, thereby showing that V(IV) does noteffectively catalyze the carbonylation reaction at the conditions used.

It will be understood that each of the elements described above, or twoor more together, may also find utility in applications differing fromthe types described herein. While the invention has been illustrated anddescribed as embodied in a method and catalyst system for producingaromatic carbonates, it is not intended to be limited to the detailsshown, since various modifications and substitutions can be made withoutdeparting in any way from the spirit of the present invention. Forexample, additional effective IOCC compounds can be added to thereaction. As such, further modifications and equivalents of theinvention herein disclosed may occur to persons skilled in the art usingno more than routine experimentation, and all such modifications andequivalents are believed to be within the spirit and scope of theinvention as defined by the following claims.

What is claimed is:
 1. A carbonylation catalyst system, comprising aneffective amount of a palladium source and catalytic amounts of aninorganic co-catalyst comprising bismuth, said effective and catalyticamounts being amounts capable of increasing the yield of aromaticcarbonate in the reaction of an aromatic hydroxy compound, carbonmonoxide and oxygen or increasing selectivity of said reaction towardaromatic carbonate.
 2. The carbonylation catalyst system of claim 1,comprising a catalytic amount of a combination of inorganic co-catalystscomprising bismuth and copper.
 3. The carbonylation catalyst system ofclaim 2, wherein the combination of inorganic co-catalysts furthercomprises titanium.
 4. The carbonylation catalyst system of claim 2,wherein the combination of inorganic co-catalysts further comprisesiron.
 5. The carbonylation catalyst system of claim 1, comprising acatalytic amount of a combination of inorganic co-catalysts comprisingbismuth and cerium.
 6. The carbonylation catalyst system of claim 1,comprising a catalytic amount of a combination of inorganic co-catalystscomprising bismuth and manganese.
 7. The carbonylation catalyst systemof claim 6, wherein the combination of inorganic co-catalysts furthercomprises europium.
 8. The carbonylation catalyst system of claim 6,wherein the combination of inorganic co-catalysts further comprisesiron.
 9. The carbonylation catalyst system of claim 6, wherein thecombination of inorganic co-catalysts further comprises cerium.
 10. Thecarbonylation catalyst system of claim 1, comprising a catalytic amountof a combination of inorganic co-catalysts comprising bismuth andeuropium.
 11. The carbonylation catalyst system of claim 1, comprising acatalytic amount of a combination of inorganic co-catalysts comprisingbismuth and nickel.
 12. The carbonylation catalyst system of claim 1,comprising a catalytic amount of a combination of inorganic co-catalystscomprising bismuth and zirconium.
 13. The carbonylation catalyst systemof claim 1, comprising a catalytic amount of a combination of inorganicco-catalysts comprising bismuth and zinc.
 14. The carbonylation catalystsystem of claim 1, comprising a catalytic amount of a combination ofinorganic co-catalysts comprising bismuth and iron.
 15. Thecarbonylation catalyst system of claim 1, comprising a catalytic amountof a combination of inorganic co-catalysts comprising bismuth andcobalt.
 16. The carbonylation catalyst system of claim 1, comprising acatalytic amount of a combination of inorganic co-catalysts comprisingbismuth and iridium.
 17. The carbonylation catalyst system of claim 1,comprising a catalytic amount of a combination of inorganic co-catalystscomprising bismuth and ruthenium.
 18. The carbonylation catalyst systemof claim 1, comprising a catalytic amount of a combination of inorganicco-catalysts comprising bismuth and rhodium.
 19. The carbonylationcatalyst system of claim 1, comprising a catalytic amount of acombination of inorganic co-catalysts comprising bismuth and a substanceselected from the group consisting of copper; copper and titanium;copper and iron; cerium; manganese; manganese and europium; manganeseand iron; manganese and cerium; europium; nickel; zinc; iron; cobalt;iridium; ruthenium; rhodium; and zirconium.
 20. The carbonylationcatalyst system of claim 1, wherein the palladium source is a Pd(II)salt or complex.
 21. The carbonylation catalyst system of claim 20,wherein the palladium source is palladium acetylacetonate.
 22. Thecarbonylation catalyst system of claim 1, wherein the palladium sourceis supported Pd.
 23. The carbonylation catalyst system of claim 22,wherein the palladium source is palladium on carbon.
 24. Thecarbonylation catalyst system of claim 1, further comprising an a halidecomposition.
 25. The carbonylation catalyst system of claim 24, whereinthe halide composition is tetraethylammonium bromide.
 26. Thecarbonylation catalyst system of claim 24, wherein the halidecomposition is hexaethylguanidinium bromide.
 27. The carbonylationcatalyst system of claim 1, wherein the molar ratio of bismuth relativeto palladium is between about 0.1 and about 100.